The Oregon Direct Legislation League was an organization of political activists founded by William S. U'Ren in the U.S. state of Oregon in 1898. U'Ren had been politically activated by reading the influential 1893 book Direct Legislation Through the Initiative and Referendum,  and the group's founding followed in the wake of the 1896 founding of the National Direct Legislation League, which itself had its roots in the Direct Legislation League of New Jersey and its short-lived predecessor, the People's Power League. 
The group led efforts in Oregon to establish an initiative and referendum system, allowing direct legislation by the state's citizens. In 1902, the Oregon Legislative Assembly approved such a system, which was known at the time as the Oregon System.
- Sullivan, James William (1893). Direct Legislation Through the Initiative and Referendum. True Nationalist Publishing Company.
- Schmidt, David D. (1989). Citizen Lawmakers: The Ballot Initiative Revolution. Philadelphia, PA: Temple University Press. pp. 7, 262.
- "Initiative, Referendum and Recall Introduction". Oregon Blue Book. Salem, Oregon: Oregon Secretary of State. 2006. Retrieved 2006-12-29.
- Carey, Charles Henry (1922). History of Oregon. Chicago, Illinois: Pioneer Publishing. pp. 837–838.